PRPF40B is a member of the RNA splicing machinery which has been reported to be rarely mutated (less than 5%) among cases of acute myeloid leukemia, myelodysplasia, chronic myelomonocytic leukemia and myeloproliferative neoplasms. Mutations in PRPF40B are typically missense mutations that may be located throughout the gene. PRPF40B mutations tend to be exclusive of other mutations in the spliceosome pathway.